Heating apparatus



' Panted Oat. 3., 1922..

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ATTORNEY z SHEETS-SHEET 2.

. s. SCOTT.

Patenmd Oct. 3, T922.

HEATING APPARATUS. APPLICATION FILED SEPT. I6, 19.18.

Patented #if 3, 1922.

i f lT D STATES PATENT orric..

WRT S. SCOTT, 0F EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR T WESTINGHOUSEELECTRIC & MANUFACTURING COMPANY, A CQRPORATION OF PENNSYLVANIA.

HEATING APPARATUS.

Application led September 16, 1918.

To all t0/om 'it may concern.'

Be it known that l, VVInr S. SCOTT, a citizen of the United States, anda resident of Edgewood Park, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in HeatingApparatus, of which the following is a specification.

rlhis invention relates to an apparatus for reducing the heat lossesincurred by the ventilation of heating chambers, ovens, drying rooms,furnaces, etc., and particularly to systems of ventilation forelectrically heated japanning and enamelling ovens.

In baking japan and enamel on materials, as well as in baking or dryingvarious other con'lpounds, compositions or materials, va-

pors or gases are formed during the dryingout process, and a certainamount of oxygen is required for the hardening of the composition,compound or material. ln order to remove these vapors and gases asrapidly as they are formed, or as rapidly as may be necessary, and tosupply the necessary oxygen for completing the oxidation process, apositive circulation must be maintained and fresh air must be suppliedto the chamber, oven or drying room.

rlhe present practice is to provide ventilating ducts and pipes for theremoval of the vapors and .gases but no provision is made for supplyingthe necessary fresh air, the supply of fresh air being derived almostentirely from leakage in and around the doors, pipe openings and othercrevices. Consequently, either an insufficient amount or an excessamount o-f air is sup lied to the heating chamber, and it is there orepractically impossible to maintain a uniform temperature throughout theinterior of the heating` chamber.

.he object of my invention is, therefore, first, to provide aVentilating system for controlling the circulation of air and gasesthrough the heating chamber that shall maintain substantially uniformtemperature throughout the interior of the chamber; secondly, totransfer as much heat as posslble from the discharged volatile andheated gases to the ingoi'ng fresh alr; thlrdly, to

vintroduce the ingoing air and withdraw the Serial No. 254,382.

to support the electric heating means from the ceiling of the chamberadjacent the`fresh air inlets and above the volatile gas zone so thatthe electric heaters shall be moreeffective.

The above and other objects and the novel features of my invention willbe apparent from the following description taken in connection with thedrawing in which Figures 1 and 2 are, respectively, a side elevation andan end elevation of a japanning and enamelling oven embodying myinvention; Fig. 3 is a longitudinal sectional view of the same on alarger scale and taken on the line Ill-Ulf of Fig. 2, and Figs. 4 and 5are sideelevational views of other forms of enamelling and japanningovens, also embodying my invention.

While l have shown my invention as applied to an electrically heatedjapanning and enamelling oven, it is, of course, to be understood thatvarious features thereof may be utilized equally well in connection withdrying rooms, furnaces, etc. Referring to the drawing, the oven 10 maybe of the usual or any preferred form, provided with doors" at the endsthereof to introduce into the chamber C and withdraw therefrom, thearticles to be treated. The air-inlet duct l1, supported from, oradjacent to, the ceiling of `the chamber C, has a series of openings 12to distribute the incoming fresh air throughout the upper portion of the.chamber, and suitable electric heating devices 13 may also be supportedadjacent the openings 12 to heat the incoming air and the interior ofthe chamber. The outlet duct 14, extending the length of the chamber Cis supported upon. the Hoor of the chamber and has a series of intakeopenings 15 to conduct away the vapors and gaseous mixtures formedwithin the chamber. l

In order to utilize some of the heat of the discharged volatile gases, Iemploy an economizer or preheating apparatus E, which is mounted uponthe roof of the oven. The economizer has heat-insulating exterior walls16, sheet-metal partitions 17, and sheet-metal baille plates 18 toprovide two winding or tortuous parallel passages 19 and 20,constituting, respectively, the freshair inlet passage and thegaseous-mixture outlet passage. The outlet passage 20 contains drip pans21 which are adapted to collect the condensed vapors and such solidmatter as may be carried off with the hotl gases and deposited in theeconomizer. The fresh-air inlet and vapor outlet passages 19 and 20,being separated merely by a metal partition 17, provide means wherebyheat may be transferred from the outgoing heated gas in the passage 20to the incoming fresh air in the'passage 19. The passage 19 is connectedto the ducts 11 within the chamber C and a header 22 leads the outgoinggaseous mixture from the` duct 14 to the passage 20. l

The other ends of both passages 19 and 20 communicate with theatmosphere, and, in order to produce a positive circulation through theeconomizer passages and the heating chamber, I provide a blower 23 whichhas its outlet connected to the incoming air passages 19. A blower isordinarily required for forcing the circulation but may, of course, beomitted where natural draft is employed.

Fig. ltshows an oven equipped with a stack S for producing a positivecirculation naturally.y In this arrangement, the fresh-V air passage 19is connected to an annular passage 25 that is open to the atmosphere atthe top under the hood 26 and surrounds the pipe 27. The pipe 27 isconnected to, and carrles olf the'volatile gases from, the passage 20,and is open at its upper end be neath the hood 28. Otherwise, thestructure shown in Fig. 4; is similar to the one disclosed in Figs. 1, 2and 3, and has the added advantage that additional heat is transferredfrom the outgoing gas to the incoming air through the metal wall of theFpipe 27.

`ing gases in the pipe 271 to the incoming fresh air flowing through thepipe 251 provides suiicient preheating of the ingoing air. In otherrespects, the oven structure shownin Fig. 5 is similar to the one shownin Figs. 1 to 3.

An oven constructed according to my invention requires much less powerfor ventilation and operation than those in use at the present time. Bythe utilization of the exhaust gases `for lheating the incoming freshair, the costof operation is materially reduced, and a uniformtemperature may also be more easily maintained. Heretofore,

the temperature in the upper part of the oven has been anywhere from 75to 200 F. hotter than the lower part. With my Ventilating system, thevolatile and heated gases that naturally tend to rise to the upperportion of the chamber are forced down by or baking. A circulationthrough the oven and a uniform temperature therein also eliminates thedanger from tires and explosions.

By locating electric heaters in the upper part of the heating chamberadjacent to the air inlets they will be out of the volatile Zone andwill occupy what is otherwise waste space inthe oven. The volatilegases, being heavier than air, settle to the bottom of the oven andheaters which are placed on the floor or side walls are constantlybathed in these frases and do not operate at their highest ehciency. Theheaters suspended from the 4ceiling are out of the way of the worlo menand are in a most advantageous posi- A l'the heaters. With the heaterslocated on the ceiling, the radiant heat is distributed uniformly over alarger area, thereby reducing the time required for baking and providingal substantially uniformy temperature, as a result of which the productwill be of a much more uniform and durable quality.

While I have shown and described, in detail, the features of the heatingchamber or oven embodying my invention, itis to be understood thatvarious modifications may be made therein without departing from thespirit and scope of the invention, as expressed in the appended claims.

I claim as my invention:

1. The combination with a heating cha ber having an outlet in the lowerpart thereof for heated gas and an inlet in the upper part thereof forcooler gas, electric heating means in the upper part of said chamberonly adjacent said inlet for heating said incoming cooler gas, wherebythe heatedgas travels downwardly and a substantially uniform temperatureis maintained within the chamber, and means whereby heat is transferredfrom the heated gas after it is discharged to the cooler gas before thelatter enters the chamber.

2. The combination with a j apanningl and ena-maling oven, of electricmean`s located-at the top only of said oven, meansfor leading a heatedgaseous mixture from the lower part of said oven, meansfor leadingcooler gas into theupper part of said oven past masones derived fromsaid heated gaseous mixture after the latter discharges from the oven,said means comprising a plurality of connected passageways for saidheated gaseous mixture, and a plurality of connected passageways for thecooler gas, said passageways being located in opposed interttingside-by-side relation and means in the passageways for the heatedgaseous mixture for collecting substances deposited from the gaseousmixture flowing therethrough.

3. The combination with an oven struc-- ture comprising a chamberhavingl an air inlet adjacent the top thereof and a gaseousmixtureoutlet adjacent the bottom thereof, of electricheatng means adjacent tosaid air inlet at the top of said chamber for heating said incoming air,means for pre-heating the air before it enters said chamber by heatderived from the gaseous mixture discharged from said outlet, and meansfor positively causing circulation through said air-heating means intosaid chamber and out of the latter through said outlet.

ft. lin a japanning and enanielling apparatus, the combination with anoven having a series of air inlets adjacent the upper wall thereof and aseries of volatile-gas outlets adjacent the lower wall thereof, of.electric heating means ladjacentsaid air inlets and above thevolatile-gas zone, meanswhereby the air is preheated, and means forproducing a positive circulation through said oven from said inlets tosaid outlets, the arrangement being such that a substantially uniformtemperature is produced throughout the interior of the oven.

5. The combination with a heatingchamber having an inlet and an outlet,of an economizer or preheating apparatus comprising parallel elongatedpassages .connected to said inlet and said outlet, respectively, andarranged in side-by--side relation,

whereby the ingoing gas may derive neat from the outgoing gas, and meansin the outlet passage for collecting the substances deposited from thegases passing therethrough.

ln, testimony whereof, l have hereunto subscribed my name this th day ofAug., 1918.

RT S.' SCGTT.

